Abstract. The isotopic composition of atmospheric water vapour at the land surface has been continuously monitored at the Kourovka astronomical observatory in western Siberia (57.037° N, 59.547° E; 300 m a.s.l.) since April 2012. These measurements provide the first record of δD, δ18O and d-excess in this region. Air was sampled at 8 m height within a forest clearing. Measurements were made with a wavelength-scanned cavity ring-down spectroscopy analyzer (Picarro L2130-i). Specific improvements of the measurement system and calibration protocol have been made to ensure reliable measurements at low humidity during winter. The isotopic measurements conducted till August 2013 exhibit a clear seasonal cycle with maximum δD and δ18O values in summer and minimum values in winter. In addition, considerable synoptic timescale variability of isotopic composition was observed with typical variations of 50–100‰ for δD, 10–15‰ for δ18O and 2–8‰ for d-excess. The strong correlations between δD and local meteorological parameters (logarithm of humidity and temperature) are explored, with a lack of dependency in summer that points to the importance of continental recycling and local evapotranspiration. The overall correlation between δD and temperature is associated with a slope of 3‰ °C−1. Large d-excess diurnal variability was observed during summer with up to 30‰ decrease during the night and the minima manifested shortly after sunrise. Two dominant diurnal cycle patterns for d-excess differing by the magnitude of the d-excess decrease (21‰ and 7‰) and associated patterns for meteorological observations have been determined. The total uncertainty of the isotopic measurements was quantified as 1.4–11.2‰ for δD, 0.23–1.84‰ for δ18O and 2.3–18.5‰ for d-excess depending on the humidity.

Abstract. Global warming is associated with large increases in surface air temperature in Siberia. Here, we apply the isotope-enabled atmospheric general circulation model ECHAM5-wiso to explore the potential of water isotope measurements at a recently opened monitoring station in Kourovka (57.04 • N, 59.55 • E) in order to successfully trace climate change in western Siberia. Our model is constrained to atmospheric reanalysis fields for the period 1957-2013 to facilitate the comparison with observations of δD in total column water vapour from the GOSAT satellite, and with precipitation δ 18 O measurements from 15 Russian stations of the Global Network of Isotopes in Precipitation. The model captures the observed Russian climate within reasonable error margins, and displays the observed isotopic gradients associated with increasing continentality and decreasing meridional temperatures. The model also reproduces the observed seasonal cycle of δ 18 O, which parallels the seasonal cycle of temperature and ranges from −25 ‰ in winter to −5 ‰ in summer. Investigating West Siberian climate and precipitation δ 18 O variability during the last 50 years, we find long-term increasing trends in temperature and δ 18 O, while precipitation trends are uncertain. During the last 50 years, winter temperatures have increased by 1.7 • C. The simulated long-term increase of precipitation δ 18 O is at the detection limit (< 1 ‰ per 50 years) but significant. West Siberian climate is characterized by strong interannual variability, which in winter is strongly related to the North Atlantic Oscillation. In winter, regional temperature is the predominant factor controlling δ 18 O variations on interannual to decadal timescales with a slope of about 0.5 ‰ • C −1 . In summer, the interannual variability of δ 18 O can be attributed to shortterm, regional-scale processes such as evaporation and convective precipitation. This finding suggests that precipitation δ 18 O has the potential to reveal hydrometeorological regime shifts in western Siberia which are otherwise difficult to identify. Focusing on Kourovka, the simulated evolution of temperature, δ 18 O and, to a smaller extent, precipitation during the last 50 years is synchronous with model results averaged over all of western Siberia, suggesting that this site will be representative to monitor future isotopic changes in the entire region.

Latitudinal distribution of the columnar deuterium/hydrogen ratio of atmospheric water vapor, δDvap, was retrieved from high‐resolution infrared spectra. Interferometric Monitor for Greenhouse gases (IMG) sensor aboard the ADvanced Earth Observing Satellite (ADEOS) observed the spectra over the ocean during the operational period from December 1996 through June 1997. The latitudinal mean δDvap was relatively large with values around −100‰ in the tropical region decreasing down to minimal values of −800‰ at high latitudes. For retrieving δDvap, a type of spectral fitting method was adopted using a forward/retrieval calculation code developed by Gribanov et al. [2001]. This method is expected to be applicable for data analyses of future satellite sensors such as IASI and TES.

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Abstract. The isotopic composition of atmospheric water vapour at the land surface has been continuously monitored at the Kourovka astronomical observatory in Western Siberia (57.037° N, 59.547° E, 300 m a.s.l.) since April 2012. These measurements provide the first record of δD, δ18O and d-excess in this region. Air was sampled at 8 m height within a forest clearing. Measurements were made with a Wavelength-Scanned Cavity Ring Down Spectroscopy analyzer. A specific protocol was developed for calibration and drift corrections with a particular enhancement to ensure reliable measurements at low humidity during winter. The isotopic measurements conducted till August 2013 exhibit a clear seasonal cycle with maximum δD and δ18O values in summer and minimum values in winter. In addition, considerable synoptic timescale variability of isotopic composition was observed with typical variations of 50–100‰ for δD, 10–15‰ for δ18O and 2–8‰ for d-excess. The strong correlations between δD and local meteorological parameters (logarithm-of-humidity and temperature) are explored, with a lack of dependency in summer that points to the importance of continental recycling and local evapotranspiration. The overall correlation between δD and temperature is associated with a slope of 3‰ °C−1. Large d-excess diurnal variability was observed during summer with up to 30‰ depletion during the night and the minima manifested shortly after sunrise. The accuracy of the isotopic measurements was quantified as 1.4–11.2‰ for δD and 0.23–1.84‰ for δ18O depending on the humidity.